A description of which data are stored on a CD-record and how the same are processed, is set forth in the publication "Zusammenstellen eines CD-Programms" (composition of a CD-program) in Funkschau No. 15, Jul. 18, 1986 on the pages 26 to 28.
Every CD-record contains an index, in which data are stored, which give a information about the number of program blocks, the start times of the latter, and the total playing time of the record. The individual program blocks normally contain pieces of music, but may also contain, for example, spoken text or various sound effects for the setting to music (or noises) of films and photographic slides. Up to 99 program blocks can be stored on a CD-record, but typically only 10 to 20 varying pieces of music are stored on a CD-record.
The index of a CD-record has the data representation shown in the figure. In the first block A0 is the title of the first piece of music, in the second block A1 the title of the last piece of music and in the third block A2 is written the total playing time of the CD-record. In the following blocks D1 to Dn are the starting times of the separate n pieces of music, which are recorded on the CD-record. The blocks A0, A1, A2, and D1 to Dn are combined to one group G1, in which the index of the CD-record is completely stored.
The total storage space provided on a CD-record for the index is completely occupied with several of the groups, for example, G2 and Gm, directly following each other, so that the data of the index of the CD-record are stored with multiple redundancy.
During playback, the starting time data D1 to Dn, in which as many as three pieces of music make up the largest part of the data stored in the index, serves to calculate the starting times of the separate pieces of music.
After insertion of a CD-record into the CD-player the separate titles of the index are read from the CD-record and stored in the memory of the CD-player. Usually the available storage space is sufficient for all titles. But there also exist CD-records with more titles than can be accommodated by the space in the memory of the CD-player. If for instance the CD-player can store ten titles, but on the inserted CD-record there are twenty titles recorded, the times of access to the unstored titles are raised. That is, because the first ten titles are stored in the memory of the CD-player, the access time to these titles is in fact small, but for the unstored remaining ten titles, the access time would be disproportionate great.